Caveat: Opera's browser and email client are not supported by IS&T. This article is based on my own experience with Opera running on Windows XP and RHEL 4, and can't be guaranteed to work for you.
Anyway, disclaimers aside, Opera's built in email client can be used to manage email on MIT's Exchange server by using IMAP functionality. Assuming you know how to create a mail account in Opera (choose IMAP as the account type), here are the important settings:
Replace "yourkerberosname" with... well, your kerberos name, and you should be all set.